The legislation on onboard diagnosis for motor vehicles requires that emission-relevant sensors, such as an environmental pressure sensors or temperature sensors be monitored with regard to their functionality. In order to ensure this, a monitoring method is normally used which requires certain stable operating states of the motor vehicle. The offset of a sensor is able to be ascertained, for example, by comparing measured values directly after a cold start of the internal combustion engine, at different times, at different places. If the offset of a sensor is too large, that is, it is outside a tolerance range, one may assume that the sensor is working in a faulty manner.
The disadvantage with known methods is that, depending on the type of sensor to be monitored, redundant sensors have to be present. In a comparison of only 2 present sensors, it cannot be readily determined which of the sensors is operating in a faulty manner. In addition, the abovementioned method cannot be used at all times, since stable operating states of the internal combustion engine have to be present.